The present invention is directed toward a chromatography vial and more particularly, toward a limited volume insert fused within the vial and a process for forming the same so that the insert is supported by the vial.
Chromatography vials typically contain limited volume inserts where the insert is secured within the vial, usually by being thermally fused to the top or the neck of the vial. As is well known in the art, the insert carries the sample to be tested while the vial provides support for the insert. There are several advantages to this type of structure as opposed to an insert merely being placed within a vial. For example, because the insert is bonded to the vial, the analyst need not waste time placing the insert within the vial himself and making certain that it is supported. Also, this arrangement allows for uniformity of results and a reduction in costs in that the autosampler may be programmed to extract the maximum amount of sample from each vial because each insert is it at a fixed height within the vial. Furthermore, no part of the sample will be lost between the insert and the vial, thereby avoiding waste and possible cross-contamination.
Another advantage of securing an insert within a vial is that several types of vials may be used with the insert. For example, one type of vial which may be used has screw threads on the neck at its open end so that a cap may be screwed onto the vial. Another type of vial has a reduced diameter neck so that a cap may be snapped onto the vial. Also, the vial may be of the type where an aluminum cap is crimped onto the top.
As much as fusing an insert to a vial has certain advantages there are, however, some problems associated with each type of insert bonded vial described above. For example, the snap on cap type of vials do not seal the vial well for long periods of time, thereby causing inaccurate results. The problem with the crimped on caps is that the caps are difficult to remove. This difficulty becomes a problem because EPA regulations require that the vial be emptied before disposal. Screw threaded vials are easy to open and seal well. However, the insert cannot be thermally fused to the top or neck of the vial using conventional techniques without the threads being distorted and damaged. This damage interferes with the cap's ability to screw onto the vial properly.
U.S. Pat. No. 5,382,409 to Baxter discloses a support for a vial where the support is contoured to fit the tapered shape of the vial so that the vial is friction fit within the support. The problem with this structure, however, is that the support does not fully encase the vial. Therefore, the sample within the vial is not fully protected. That is, sample may be lost between the vial and the support. Also, cross-contamination may occur.